When using PubMed, make sure and go to the Woodruff Health Sciences Center Library’s homepage at http://health.library.emory.edu and click PubMed or use this direct link to Emory University’s instance of PubMed: http://www.ncbi.nlm.nih.gov/pubmed?otool=emorylib. When using Emory University’s instance of PubMed, you will be able to click the Find it at Emory button within entries for articles to determine if Emory has full-text access to articles.

Here is the search technique I used:
(early ambulation OR “early mobility”) AND (critical care OR intensive care units OR icu) AND length of stay
Filters I used: meta-analysis, systematic review, English

Please paste the following search into PubMed to see 8 articles that appear to be helpful and are systematic reviews, one of the highest levels of evidence.

24424616[uid] OR 23127305[uid] OR 24222709[uid] OR 22147819[uid] OR 21164413[uid] OR 21169829[uid] OR 20048676[uid] OR 20001881[uid]